Mastering JavaScript

Data Structures and Manipulation
One critical variation of this pattern is a range of values. If we want to match against
a sequential range of characters or numbers, we can use the following pattern:
var pattern = /[0-5]/;
console.log(pattern.test(3)); //true
console.log(pattern.test(12345)); //true
console.log(pattern.test(9)); //false
console.log(pattern.test(6789)); //false
console.log(/[0123456789]/.test("This is year 2015")); //true
Special characters such as $ and period (.) characters either represent matches to
something other than themselves or operators that qualify the preceding term. In
fact, we've already seen how [, ], -, and ^ characters are used to represent something
other than their literal values.
How do we specify that we want to match a literal [ or $ or ^ or some other special
character? Within a RegEx, the backslash character escapes whatever character
follows it, making it a literal match term. So \[ specifies a literal match to the [
character rather than the opening of a character class expression. A double backslash
(\\) matches a single backslash.
In the preceding examples, we saw the test() method that returns true or false
based on the pattern matched. There are times when you want to access occurrences
of a particular pattern. The exec() method comes in handy in such situations.
The exec() method takes a string as an argument and returns an array containing all
matches. Consider the following example:
var strToMatch = 'A Toyota! Race fast, safe car! A Toyota!';
var regExAt = /Toy/;
var arrMatches = regExAt.exec(strToMatch);
console.log(arrMatches);
The output of this snippet would be ['Toy']; if you want all the instances of the
pattern Toy, you can use the g (global) flag as follows:
var strToMatch = 'A Toyota! Race fast, safe car! A Toyota!';
var regExAt = /Toy/g;
var arrMatches = regExAt.exec(strToMatch);
console.log(arrMatches);
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